Battery String Resistance Measurement via DC Voltage Control
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Solution Overview
Problem
The condition of rechargeable batteries used in backup power systems is difficult to monitor, especially when they are not actively providing power, due to increasing internal resistance and other degradation factors, which can lead to reduced capacity and voltage drop, affecting their ability to deliver power during outages.
Innovation Solution
A method and apparatus for measuring and monitoring the resistance of battery strings by using existing DC power supply capabilities, such as control of output voltage and current measurement, with manual or automatic initiation, comparison to preset thresholds, and display of results, to assess the change in resistance over time and detect potential failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If batteries are not actively providing power during normal operation, then energy consumption is reduced and battery life is extended, but the condition of the batteries remains unknown and degradation cannot be monitored
Solution Approach 1:
The battery string monitors itself by utilizing its own electrical characteristics (voltage, current, resistance) during normal operation to assess its condition. The system performs self-diagnosis through automatic initiation of measurement cycles that evaluate battery performance parameters without requiring external intervention or removing the battery from service.
Solution Approach 2:
The system continuously monitors battery resistance and compares measured values against baseline data and thresholds to provide feedback on battery degradation. This feedback mechanism enables early detection of condition changes and triggers alerts when performance parameters exceed predetermined limits, allowing proactive maintenance before failure occurs.
2Reliability
If internal resistance of batteries increases over time, then battery capacity degrades and voltage drop increases, but measuring this change requires active intervention and complex measurement procedures
Solution Approach 1:
The measurement system utilizes existing DC power supply capabilities and standard multimeter functions to perform multiple battery assessment tasks. The same hardware infrastructure supports both normal power supply operations and resistance measurement functions, eliminating the need for separate specialized measurement equipment and reducing overall system complexity.
Solution Approach 2:
The system replaces complex manual measurement procedures with automated electronic measurement and processing. Instead of requiring physical disassembly, external testing equipment, or manual calculations, the system uses electronic sensors, microprocessors, and algorithmic analysis to automatically determine battery resistance and compare it against baseline data.
3Ease of operation
If battery resistance measurement is performed manually or at scheduled intervals, then some monitoring is achieved, but timely detection of degradation and potential failures is delayed
Solution Approach 1:
The system performs preliminary measurements of battery resistance at regular intervals during normal operation to establish current performance baselines. These preliminary actions enable the system to detect degradation trends early and compare them against historical data, triggering timely alerts before complete failure occurs.
Solution Approach 2:
The battery monitoring system operates continuously during normal power supply operations, automatically initiating measurement cycles without interruption to battery service. This continuous monitoring ensures that degradation is detected in real-time rather than at discrete scheduled intervals, eliminating downtime and maintaining constant awareness of battery condition.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for accurate and timely monitoring of battery string resistance, enabling early detection of degradation and potential failures, thus ensuring reliable backup power supply during outages by comparing measured resistance values with baseline data and generating alarms when thresholds are exceeded.
Implementation Method 1
the resistive component of the impedance is of interest as the discharge current produces a voltage drop across the internal resistance of the battery in accordance with Ohm's law
Data Source
AI summary
A DC power supply system in which the resistance of a battery is measured. The voltage of the DC power supply is reduced such that the battery supplies some current to the load, and the voltage and current are measured. The voltage of the DC power supply is further reduced such that the battery supplies increased power to the load, and the voltage and current are measured. A resistance value is computed, and may be compared with various pre-established criteria. The battery resistance may also be measured by comparing the charging time of a known resistive-capacitive circuit with the charging time established at a prior measurement epoch.